I'm trying to figure out the temperature on my Fenix LD15, but it's not in the specs. Does anybody know how to calculate it from other specs?

Do you have the full code that describes what kind of LED it has? (In the specs, on some receit, or packaging or whatever...) Given enough digits in the code, you may or may not find enough details to dig out color temp for that particular diode. Google is your friend here...

Example: A led of type "Cree XR-E" doesn't really tell you anything, those come in all kinds of color temperatures. But if there's additional digits you may have enough information.

Another source of information could be reviews for LD15, written about the same time as your purchase. They may have written something about color temp.

Fenix -- like most LED lights -- tend to be somewhere in the "colder part of the range "cold" to "neutral".

I received the 4000k version of this flashlight. The diagram above provided by Alex is fairly accurate. Compared to the Fenix LD15, this 4000k flashlight has a "warmer" color appearance. (So, the 3000k has an even warmer color appearance.) The LD15 looks to be about 5000k. I don't think I want a beam that's less than 4000k. The high settings have roughly the same brightness, and roughly the same size spotlight, to my eyes.

This stainless steel flashlight is smaller (thinner and shorter) compared to the LD15. The shorter length surprised me because the paper specifications of the LD15 show less length, but that is not actually the case.

Downsides... A downside to the LD15 is the twist switch. I prefer a button switch. Also, the LD15 is slightly bigger. A downside to this 4000k flashlight is the way it heats up if you run the flashlight on high for awhile. Aluminum (LD15) is better at dissipating heat than stainless steel (this 4000k). Another downside of this 4000k is my switch doesn't lock to the last setting when I turn it off. It cycles to the next intensity (high, medium, or low). Yes, my flashlight came with 3 levels, not 2.

I haven't yet decided which one I like better. It's roughly a draw at this point.

Missed this one. Nice comparison review. I've got mine as well. The 3000K is definitely more reddish tinted, but I love that incandescent feel, it seems adding some contrast in a total darkness scene.

I would not be concerned much with the overheating. Modern LEDs are constructed with the account for that, and this particular one is not really an ultra powerful model. Quite contrary the steel shell's heat propagation resistance should reduce the overheating chance for the battery.

Alex, my 4000k is the most incandescent-looking color of all my LED flashlights. Is your 4000k also incandescent-looking relative to other flashlights? Maybe I actually received the 3000k, but I'm not going to order a 3000k to find out.

The 4000K one is close to an incandescent too, but more like a bright halogen lamp to me. 3000K feels like a 25 W ceiling bulb light or halogen on minimum settings, noticeably more reddish. The color chart above interprets it quite realistically. My older LED lights are definitely something bluish between 5-7kK.